Detergent bars



vii-34 DETERGENT BARS Fred E. Boettner, Philadelphia, and James L. Rainey,

Abington, Pa., assignors to Rohm & Haas Company, Philadelphia, Pa, a corporation of Delaware No Drawing. Filed May 27, 1957, Ser. No. 661,9 66

12 Claims. 01. 252-152) This invention relates to a new and useful detergent United States Patent-O 2,982,737 Patented May 2, 1961 2 be verysuccessful in accomplishing this object, comprises a detergent =bar whose principal components are a glucose derivative, namely N-methyl-N-sorbityl lauramide, sodium lauryl sulfate,'and urea. The lauramide is melted and reacted with the .urea. The product of this react-ion is mixed with the sodium lauryl sulfate, cooled and then kneaded together to reduce the crystalline structure befgre molding. Fillers such as talc, bentonite, Attapulgus clay or, starch, may be added to obtain various properties has long been recognized. Expensive experimental work 1 has been devoted to this objective as can be seen from a number "of articles which have been published in Soap and Sanitary Chemicals, including Synthetic Detergents in Bar Form by J. W. McCutcheon (December 1949,

,or characteristics which are commercially desirable. Perfum e ;and/orcoloring matter may be added for appearance or aesthetic efiects.

Manufacture of the detergent bars of the present invention is.quite simple, and is completely free of the shortcomings described above relative to manufacturing prior artbars. To begin with, the reaction of urea and the N-methyl-N-sorbityl lauramide proceeds very readily to-givea clear melt at a low temperature and at atmospheric-pressure. Mixing this reaction product together with the other active component, sodium lauryl sulfate, is also no problem asthe two are quite compatible and again the result is a clear melt. When this melt is sufficiently co oled,.'a hard mass is formed which can be 1 kneaded-by hand at about 50-60" C. for a considerablepages 33 et seq.), Hard WaterBar Soaps by -M. A.

Lesser (June 1950, pagesf42 etseq.), Toilet Bar Form synthetics by V. I. Keenan (May 1951, pages'2 7 et seq.), and f Milled Detergent Bar by Jelinek, Mayhew and Yeager (August 1952). Notwithstanding intensive efiorts by many workers in thefifield for manyyears, no

bar has been made whose active cleansing agentsjare comprised wholly of synthetic organic detergents and which has met with wide consumer acceptance.

. There are a number of reasons why a detergent bar isto be preferred over soap. For example, soap bars tend to form scum whichis particularly noticeable and objectionable in a wash basin or tub. Soapbars have poor lathering qualities, especially in hard water, shortlength of time. ,The materials harden on standing about twenty-four hours or longer. g I I .-.The invention will be;illustratedbelow by a number ofspecificexamples. Priorthereto, however, some gen- .eral considerations will be set,forth in order to assist thosewho would practice this invention. To begin with, the amounts ofthe principal components should be 1 chosen fromthe following ranges (in all cases through comings which detergentsshould overcome. However,v in comparison with soap, detergent bars generally have been 5 found to be more costly, more 'ditlicult-to process, and

so water-soluble as to beshort-lived. Detergent bars in the .past have exhibited a very .poor slush resistance? (i.e. tendency to resist softening onresting in lwetjsocalled .soap dishes),.andtendtocrack or split onstorage. 7 They leave a sticky or tacky feeling on the skin advantages described above.

after use, and lack the slippery feel-inherent in soap bars, both of which characteristics. have made detergent bars five parts, but in any event no more than ten parts.

.unpopular. Difliculties have been encountered in manufacturing the bars because most detergents wont soften under application of heat and pressure. They tend to stick to the mill rollers and wont extrude from thefplodders" a machine for extruding the bar stock).v

, To overcome some of the faults-found with prior art bars made essentially entirely from synthetic detergents,

bar compositions have been.made which, are part detergent and part soap. Other barsvhave been compounded so as to incorporate such materials as cold or cleansing creams. But the fact remains that these are. but partial solutions to the problem of findinga'way to makea wholly detergent bar which will have all the well-known advantages of synthetic detergents butpnone of the dis.-

1 It is, therefore, the principal object of this invention.

provide a synthetic detergent composition which,- in bar. 2

form,..wi1l be firm,rcohesiv'e, smooth andpleasant'tothe touch before and after use, have considerable slush' resistance, and lather, and suds well inhot and cold water. 7 1

r, In essedcathepresent invention, which has proven. to.

. reassess jiieaeergem impasse... or the out this description the values are given .as parts by Instead of the lauramide other fatty acid amides, such as N-methyl-N-sorbityl myris'tic acid amide may be used. Some amides, e.g. stearamide, which is' not as soluble as lauramide, may be used to replace a portion, but not all,

of the lauramide as too much of itgives the end product a slimy feel. When stearamide is employed it preferably should be'present in amounts ranging between two and lfilgn ethyLN-sorbityl capric acid amide is also useful for the same purpose just described for steararnide, although itmay. beus s w inla s a aat t e up s am ratio of 1 1 the lauramide. It is also satisfactory to use the N-methyl-N-sorbityl myristic acid amide to replace but a: portion of theflauramide, also upto a maximum of 1:1.

It has bee n foundthat on heating urea and N-methyl Nesorbityl lauramide a chemical reaction takes place as iollgws f Present" and urea is not permitted totake' place, as could be the case if a different order is followed in mixing the'ingredicuts or if a lower reaction temperature is employed, the desirable soap-like feel of the resulting bar will not be obtained. In the event that more than one amide is incorporated in the composition, as where both the lauramide and either the stearamide, capric acid amide, or myristic acid amide is utilized, it is essential that they be mixed together before adding the urea, else the necessary reaction between the amide(s) and urea will not occur. It, should be understood that the reaction product of the amide and urea, although having some cleansing ability, is not in itself a composition which will have all the desirable properties for a detergent bar. For one thing it has low foaming characteristics, and for another its detergency ability is not as good as that of the'preferred form of this invention. What is lacking'in this intermediate product is supplied by the sodium lauryl sulfate. This substance, in itself a very high foamer, appears to supply just the right foaming and detergency properties to the ultimate product of the present invention. 1 I

We have found, further, that the combination of urea with sodium lauryl sulfate to form a bar is unsatisfactory because the result is a'crystalline mass. But whenthe lauramide, or other suitable amide isadded, and reacted first with the urea as described above, an excellent detergent bar results. Actually, as'indicated previously,- a mini-mum'of about twentyparts by weight of the amide is essential to formation of a satisfactory product.

'The invention'is subject toa number of modifications in order to provide a product having certain'characteristics which may be especially desired by some users, as for some special purposes. For example, there may be added certain diluents such as carboxyrnethylcellulose or starch, both being well-known inert extenders which form protective colloids that increase the slush-resistance and enhance the foaming qualities of the resulting product. Another such diluent or extender ispolyacrylamide; it, too, has a protective colloid action and forms a binder for. the entire composition. v 2

Having described our invention in general terms, and devoted some of the foregoing description to incidental considerationof a general nature, we will now disclose actual examples of the practice of ourinvention.

Example 1 Composition: v V Parts N-methyl-N-sorbityl lauramide 25 Urea 25 Sodium lauryl sulfate (solid) 25 The N-methyl-N-sorbityl.lauramide was melted (ca. 80 C.) and the urea was added with stirring. This mixture was heated until molten (ca. 120 C.) and then heated to 140 C. The solid sodium lauryl sulfate was then dissolved in this molten mass with stirring. The molten material was then poured onto a large watch glass to cool. When the mixture had cooled to 50 C; it was kneaded by hand until too stiff to work (ca. 15 min)" and then molded into a bar and set aside to cool overnight. This bar was very hard and produced excellent suds in hard and soft Water; its feel was exactly like that of soap.

Example 2 Composition: Parts N-methyl-N-sorbityl lauramide 24 Urea 50 Sodium lauryl sulfate (solid) 24 Stearic acid 2 were mixed and melted ea C.). Theurea was then The -N-methyl-N soi'bityl lauramide and .stearic acid 75'.

added Withstir-ring and heating was continued until the mixture was again molten ('oa. -140 C.). The solid sodium lauryl sulfate was then added with stirring and the mixture heated until completely molten. The molten mass was then poured into a watch glass and allowed to cool. When cooled to 40-50 the material was kneaded until too stiff to handle readily and then molded into the form of a bar and allowed to age for several days. This bar was almost identical to a bar of soap in appearance,

feel and sudsing action. The bars hardness and emollient power appeared to'be improved, apparently due to the stearic acid.

The method of preparation is the same as stated Examples 1 and 2. The order of-addition of the five constituents is as set forth in the above list. The stearamide is believed to have been responsible for an evenharder bar than theone obtained in Example 2. It also served as an emollient in place-of thestearic acid which had so functioned in Example 2. The (poly) N-methyl-N-sorbityl acrylamide appeared to lessen the tackiness of the resulting product, and probably contributed to the hardness of the bar.

' Example 4 Composition: Parts N-rnethyl-N-sorbityl stearamide 1.64

N-methyl-N-sorbityl laurarnide 20.50 Urea 53.30 'Carboxymethy-lcellulose (70 high) 4.10

Sodium lauryl sulfate (Solid) 20.50 Trace of perfume, By 70 high is meant 0.7 mole of sodium carboxy methyl groups per glucose unit, the viscosity being 1300-2200 centipoises at 1% water standard 25 C. This bar was prepared in the same manner as the bars in Examples 1 to 3 above. The carboxymethyl-cellulose served the same purposes as didthe polyacrylamide in Example 3.

Having thusdescr-ibed the invention, we may conclude by stating that the detergent bars produced thereby are remarkable in'tlieir resemblance to soap bars in feel and lathering properties, yet they have been found to doa'far better'job of removing carbonblack from the hands than does soap. These new bars, although useful to all, will be especially useful to persons who are allergic to soap, for-the detergents are harmless and nonirritating for personal toilet use. in view of the novel and useful features of this invention, we claim:

11111 the method of manufacturing a detergent bar from 50 to 70 parts by weight of urea, 20 to 30' parts by weight of an amide from the group consisting of N- methyl-N-sorbityllauramide and -N-methyl-Nj-sorbityl myristic'acid amide, and 30 'to 40-parts by'weight of sodium lauryl sulfate, the steps which consist of heating 3.-The method of claim 1 in which the amide used is N-methyl-N-sorbityl myristic amide. #4. The method of claim 1 in'which up-tc 10 parts .by

weight of the amide is replaced by an equal amount of N-niethyl-N-sorbityl stearamide, the two' arnides being the amide and the urea together until a reaction takes placeiand a clear melt is formed,fintin1ately mixing the sodium lauryl sulfate withthe total product of that reac-.

in which the amide used is 5 mixed together before reaction thereof with urea, and then mixing the total product of that reaction with sodium lauryl sulfate.

5. The method of claim 1 in which up to one-half of the amide is replaced by an equal amount of an amide chosen from the group consisting of N-methyl-N-sorbityl myristic acid amide and N-methyl-N-sorbityl capric acid amide, the two amides being mixed together before reaction withurea, and then mixing the total product of that reaction with sodium lauryl sulfate.

6. The method of claim 5 in which the replaced amide is replaced with N-methyl-N-sorbityl myristic acid amide.

7. The method of claim 5 in which the replaced amide is replaced with N-methyl-N-sorbityl capric'acid amide.

8. A detergent bar prepared by the method of claim 2.

9. A detergent bar prepared by the method of claim 3.

10. A detergent bar prepared by the method of claim 4.

11. A detergent bar prepared by the method of claim 6.

112. A detergent bar prepared by the method of claim 7.

6 References Cited in the file of this patent UNITED STATES PATENTS 2,181,929 Werntz Dec. 5, 1939 2,374,187 Flett Apr. 24, 1945 2,374,213 Katzman Apr. 24, 1945 2,374,544 Hoyt Apr. 24, 1945 2,383,737 Richardson Aug. 28, 1945 2,653,932 Schwartz Sept. 29, 1953 2,667,478 Schwartz Jan. 26, 1954 2,675,356 Woodworth et al Apr. 13, 1954 2,676,955 Weitkamp Apr. 27, 1954 2,703,798 Schwartz Mar. 8, 1955 2,834,775 Boettner May 13, 1958 OTHER REFERENCES Surface Active Agents, by Schwartz et al., page 213, pub. by Interseience Pub., Inc., N.Y., 1949. 

1. IN THE METHOD OF MANUFACTURING A DETERGENT BAR FROM 50 TO 70 PARTS BY WEIGHT OF UREA, 20 TO 30 PARTS BY WEIGHT OF AN AMIDE FROM THE GROUP CONSISTING OF NMETHYL-N-SORBITYL LAURAMIDE AND N-METHYL-N-SORBITYL MYRISTIC ACID AMIDE, AND 30 TO 40 PARTS BY WEIGHT OF SODIUM LAURYL SULFATE, THE STEPS WHICH CONSIST OF HEATING THE AMIDE AND THE UREA TOGETHER UNTIL A REACTION TAKES PLACE AND A CLEAR MELT IS FORMED, INTIMATELY MIXING THE SODIUM LAURYL SULFATE WITH THE TOTAL PRODUCT OF THAT REACTION TO AGAIN FORM A CLEAR MELT, COOLING UNTIL THE MIXTURE CAN READILY BE KNEADED, AND KNEADING UNTIL THE MIXTURE BECOMES SUFFICIENTLY STIFFENED TO BE FORMED INTO THE DESIRED BAR SHAPE. 